It's one thing if you're doing it to train certain mechanics, or if you're aware enough to understand informational timings so you just don't move because it'd spawn you somewhere else since you'd take an impossible fight, but most campers are really just in it for KDR and that's about it.
Like, in my experience, people who camp look for one or two very specific spots on a map and try to get there consistently. If they can't, they die a lot, but once they're there they won't budge. It's not really a useful away of playing. Sure, they can do what they want, but in a real game of CS it's a totally pointless exercise and makes them utterly useless.
But, again, most of those types don't even play traditional CS.